Fuel Sending unit, fuel gauge, and instrument resistances.

[Bulletproof250]

I did, I swear did, search the forum for this information, or similar problem.

I installed a plastic tank 3 years ago, best thing ever. I also installed a send sending unit since the factory one was toast (gage did not work).

Everything looked OK with the install except, once I put the first 5-gallons of fuel in it, I knew something wasn't quite right, since the gage read near 3/4 tank. Hmmmm Oh well I battled with clogged fuel filters, and rebuilding carburetors way too much. I was so excited those days were behind me, that I wasn't that concerned with the fuel level too much.

That was years ago, and now I'd like to see how I can remedy the situation. So I started with the sender, It seems that the resistance is about 20 Ohms low, so that's easy I just added 20 Ohm resistor to the time, and sure enough the gage looked about right for what I estimated was in the tank. However....

2 other gages on the dash looked different, the oil pressure and the temperature, the oil pressure was higher than it had been before (mid-high vs Low-mid), and the Coolant temp did about the same.

Now hold on before you tell me the resistors are NOT the right way to fix the sender, understand that I agree, but I was looking to see if the sending unit I had was the issue, and it almost seems that there could be another factor in play here since the 2 other gages aso start to read in a more "middle of the road" measurement. since the factory gages are not annotated, there is no way to verify if they are reading accurately.

Is there anyone out here, that has had a similar experience, or expertise with the way the other gages should be reading during normal conditions?

 

[ArdWrknTrk]

If all three gauges are reading off you likely have a problem with the Instrument Cluster Voltage Regulator (ICVR) or the resistor that feeds the ICVR.

Gary has long advocated swapping this out for a solid state regulator (DE-SWADJ3) using a 9V battery connector.

This led to an epic microanalysis over on FTE.

I think he's ended up with it set at 5.4V*

You can read about it here:. http://www.garysgaragemahal.com/icvr.html

https://www.dimensionengineering.com/products/de-swadj3

 

[ArdWrknTrk]

If all three gauges are reading off you likely have a problem with the Instrument Cluster Voltage Regulator (ICVR) or the resistor that feeds the ICVR.

Gary has long advocated swapping this out for a solid state regulator (DE-SWADJ3) using a 9V battery connector.

This led to an epic microanalysis over on FTE.

I think he's ended up with it set at 5.4V*

You can read about it here:. http://www.garysgaragemahal.com/icvr.html

https://www.dimensionengineering.com/products/de-swadj3

You can see the resistance wire and how the ICVR feeds the cluster in this image from the 1985 EVTM.

Unfortunately, the 1984 EVTM in the above documentation is really just a placeholder. So this is the best I can do for you.

[Bulletproof250]

You can see the resistance wire and how the ICVR feeds the cluster in this image from the 1985 EVTM.

Unfortunately, the 1984 EVTM in the above documentation is really just a placeholder. So this is the best I can do for you.

Jim,

good Morning , Whoa you're up early!

Thanks for the quick info. When you mentioned the ETVM as a "placeholder" in the 1984's does that mean that, the "Instrument Voltage Regulator" doesn't exist in the 1984 Models? or is it just not shown as part of the schematic for those model years?

I'm currently marked it on my assignments to read Gary's post/knowledge regarding this problem.

again,

[Gary Lewis]

Jim,

good Morning , Whoa you're up early!

Thanks for the quick info. When you mentioned the ETVM as a "placeholder" in the 1984's does that mean that, the "Instrument Voltage Regulator" doesn't exist in the 1984 Models? or is it just not shown as part of the schematic for those model years?

I'm currently marked it on my assignments to read Gary's post/knowledge regarding this problem.

again,

I know you asked Jim, but I'll answer. The "placeholder" bit is just to say that while I have the '84 EVTM I've not put it on the website. That's because for all practical purposes it is the same as the '85. And yes, there is an ICVR in your truck. It was used up through '86 and then in '87 the gauges changed so it was no longer needed.

[ArdWrknTrk]

Jim,

good Morning , Whoa you're up early!

Thanks for the quick info. When you mentioned the ETVM as a "placeholder" in the 1984's does that mean that, the "Instrument Voltage Regulator" doesn't exist in the 1984 Models? or is it just not shown as part of the schematic for those model years?

I'm currently marked it on my assignments to read Gary's post/knowledge regarding this problem.

again,

If you look under Documentation>electrical>EVTM's> 19XX, you will see '1984' but it isn't fleshed out.

The wiring is so similar in 1985 (except for EFI in the 5.0l) that I guess Gary didn't feel it was worth scanning the whole book to have duplicate information.

There is definitely an ICVR in all Ford vehicles from '86 back to before I was born.

You have one, and it is the one thing common to those gauges, as you can see, in the diagram above.

I was hoping Gary would chime in since he has replaced both of his... while my '87 is the first year without one.

I do believe there is also a tutorial for retrofitting under the Bullnose Upgrades tab.

[Gary Lewis]

If you look under Documentation>electrical>EVTM's> 19XX, you will see '1984' but it isn't fleshed out.

The wiring is so similar in 1985 (except for EFI in the 5.0l) that I guess Gary didn't feel it was worth scanning the whole book to have duplicate information.

There is definitely an ICVR in all Ford vehicles from '86 back to before I was born.

You have one, and it is the one thing common to those gauges, as you can see, in the diagram above.

I was hoping Gary would chime in since he has replaced both of his... while my '87 is the first year without one.

I do believe there is also a tutorial for retrofitting under the Bullnose Upgrades tab.

Yes, there is a tutorial: Documentation/Electrical/Instrument Cluster Voltage Regulator: http://www.garysgaragemahal.com/icvr.html. And you are right, Jim. I found that 5.4 volts put the three sets of gauges I tried right where they should be. So that's the voltage I dial in.

[Bulletproof250]

Yes, there is a tutorial: Documentation/Electrical/Instrument Cluster Voltage Regulator: http://www.garysgaragemahal.com/icvr.html. And you are right, Jim. I found that 5.4 volts put the three sets of gauges I tried right where they should be. So that's the voltage I dial in.

Thanks Jim, Thanks Gary,

1. For not razzing me too much for NOT searching-before-posting

2. For the highly detailed and understandable responses.

3. For your help keeping this Bullnose alive.

[Gary Lewis]

Thanks Jim, Thanks Gary,

1. For not razzing me too much for NOT searching-before-posting

2. For the highly detailed and understandable responses.

3. For your help keeping this Bullnose alive.

Alex - We have over 550 web pages, and some of those hold multiple documents, so it can be very difficult to find things. But, since I'm the librarian I usually know where put it.

So we aren't into razzing people for not searching. Nor for much of anything else, in reality.

[ArdWrknTrk]

Thanks Jim, Thanks Gary,

1. For not razzing me too much for NOT searching-before-posting

2. For the highly detailed and understandable responses.

3. For your help keeping this Bullnose alive.

We're are all here to help each other!

I'm sorry if my saying that Gary had left a place marker seemed cryptic....

Perhaps Gary, you should just remove the 1984 heading....

I'm just glad you worked your magic, and did whatever you did so that I can access them.

It helps me a lot to leave people a link or drop an image in a reply to someone's question.